/* * MAX1117/MAX1118/MAX1119 8-bit, dual-channel ADCs driver * * Copyright (c) 2017 Akinobu Mita * * This file is subject to the terms and conditions of version 2 of * the GNU General Public License. See the file COPYING in the main * directory of this archive for more details. * * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1117-MAX1119.pdf * * SPI interface connections * * SPI MAXIM * Master Direction MAX1117/8/9 * ------ --------- ----------- * nCS --> CNVST * SCK --> SCLK * MISO <-- DOUT * ------ --------- ----------- */ #include #include #include #include #include #include #include enum max1118_id { max1117, max1118, max1119, }; struct max1118 { struct spi_device *spi; struct mutex lock; struct regulator *reg; u8 data ____cacheline_aligned; }; #define MAX1118_CHANNEL(ch) \ { \ .type = IIO_VOLTAGE, \ .indexed = 1, \ .channel = (ch), \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ .scan_index = ch, \ .scan_type = { \ .sign = 'u', \ .realbits = 8, \ .storagebits = 8, \ }, \ } static const struct iio_chan_spec max1118_channels[] = { MAX1118_CHANNEL(0), MAX1118_CHANNEL(1), IIO_CHAN_SOFT_TIMESTAMP(2), }; static int max1118_read(struct spi_device *spi, int channel) { struct iio_dev *indio_dev = spi_get_drvdata(spi); struct max1118 *adc = iio_priv(indio_dev); struct spi_transfer xfers[] = { /* * To select CH1 for conversion, CNVST pin must be brought high * and low for a second time. */ { .len = 0, .delay_usecs = 1, /* > CNVST Low Time 100 ns */ .cs_change = 1, }, /* * The acquisition interval begins with the falling edge of * CNVST. The total acquisition and conversion process takes * <7.5us. */ { .len = 0, .delay_usecs = 8, }, { .rx_buf = &adc->data, .len = 1, }, }; int ret; if (channel == 0) ret = spi_sync_transfer(spi, xfers + 1, 2); else ret = spi_sync_transfer(spi, xfers, 3); if (ret) return ret; return adc->data; } static int max1118_get_vref_mV(struct spi_device *spi) { struct iio_dev *indio_dev = spi_get_drvdata(spi); struct max1118 *adc = iio_priv(indio_dev); const struct spi_device_id *id = spi_get_device_id(spi); int vref_uV; switch (id->driver_data) { case max1117: return 2048; case max1119: return 4096; case max1118: vref_uV = regulator_get_voltage(adc->reg); if (vref_uV < 0) return vref_uV; return vref_uV / 1000; } return -ENODEV; } static int max1118_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct max1118 *adc = iio_priv(indio_dev); switch (mask) { case IIO_CHAN_INFO_RAW: mutex_lock(&adc->lock); *val = max1118_read(adc->spi, chan->channel); mutex_unlock(&adc->lock); if (*val < 0) return *val; return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: *val = max1118_get_vref_mV(adc->spi); if (*val < 0) return *val; *val2 = 8; return IIO_VAL_FRACTIONAL_LOG2; } return -EINVAL; } static const struct iio_info max1118_info = { .read_raw = max1118_read_raw, }; static irqreturn_t max1118_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct max1118 *adc = iio_priv(indio_dev); u8 data[16] = { }; /* 2x 8-bit ADC data + padding + 8 bytes timestamp */ int scan_index; int i = 0; mutex_lock(&adc->lock); for_each_set_bit(scan_index, indio_dev->active_scan_mask, indio_dev->masklength) { const struct iio_chan_spec *scan_chan = &indio_dev->channels[scan_index]; int ret = max1118_read(adc->spi, scan_chan->channel); if (ret < 0) { dev_warn(&adc->spi->dev, "failed to get conversion data\n"); goto out; } data[i] = ret; i++; } iio_push_to_buffers_with_timestamp(indio_dev, data, iio_get_time_ns(indio_dev)); out: mutex_unlock(&adc->lock); iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED; } static int max1118_probe(struct spi_device *spi) { struct iio_dev *indio_dev; struct max1118 *adc; const struct spi_device_id *id = spi_get_device_id(spi); int ret; indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); if (!indio_dev) return -ENOMEM; adc = iio_priv(indio_dev); adc->spi = spi; mutex_init(&adc->lock); if (id->driver_data == max1118) { adc->reg = devm_regulator_get(&spi->dev, "vref"); if (IS_ERR(adc->reg)) { dev_err(&spi->dev, "failed to get vref regulator\n"); return PTR_ERR(adc->reg); } ret = regulator_enable(adc->reg); if (ret) return ret; } spi_set_drvdata(spi, indio_dev); indio_dev->name = spi_get_device_id(spi)->name; indio_dev->dev.parent = &spi->dev; indio_dev->info = &max1118_info; indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->channels = max1118_channels; indio_dev->num_channels = ARRAY_SIZE(max1118_channels); /* * To reinitiate a conversion on CH0, it is necessary to allow for a * conversion to be complete and all of the data to be read out. Once * a conversion has been completed, the MAX1117/MAX1118/MAX1119 will go * into AutoShutdown mode until the next conversion is initiated. */ max1118_read(spi, 0); ret = iio_triggered_buffer_setup(indio_dev, NULL, max1118_trigger_handler, NULL); if (ret) goto err_reg_disable; ret = iio_device_register(indio_dev); if (ret) goto err_buffer_cleanup; return 0; err_buffer_cleanup: iio_triggered_buffer_cleanup(indio_dev); err_reg_disable: if (id->driver_data == max1118) regulator_disable(adc->reg); return ret; } static int max1118_remove(struct spi_device *spi) { struct iio_dev *indio_dev = spi_get_drvdata(spi); struct max1118 *adc = iio_priv(indio_dev); const struct spi_device_id *id = spi_get_device_id(spi); iio_device_unregister(indio_dev); iio_triggered_buffer_cleanup(indio_dev); if (id->driver_data == max1118) return regulator_disable(adc->reg); return 0; } static const struct spi_device_id max1118_id[] = { { "max1117", max1117 }, { "max1118", max1118 }, { "max1119", max1119 }, {} }; MODULE_DEVICE_TABLE(spi, max1118_id); #ifdef CONFIG_OF static const struct of_device_id max1118_dt_ids[] = { { .compatible = "maxim,max1117" }, { .compatible = "maxim,max1118" }, { .compatible = "maxim,max1119" }, {}, }; MODULE_DEVICE_TABLE(of, max1118_dt_ids); #endif static struct spi_driver max1118_spi_driver = { .driver = { .name = "max1118", .of_match_table = of_match_ptr(max1118_dt_ids), }, .probe = max1118_probe, .remove = max1118_remove, .id_table = max1118_id, }; module_spi_driver(max1118_spi_driver); MODULE_AUTHOR("Akinobu Mita "); MODULE_DESCRIPTION("MAXIM MAX1117/MAX1118/MAX1119 ADCs driver"); MODULE_LICENSE("GPL v2");